Work Is Funded by $513K Award from the NSF

Every year, vast quantities of carbon dioxide are released into the atmosphere by power plants burning coal and natural gas, contributing to planet-warming greenhouse gases. In 2015 alone, America’s electric power sector emitted about 1,925 million metric tons of carbon dioxide, according to the U.S. Energy Information Administration.

Converting even 1 percent of this exhaust gas into sustainable fuels would be equivalent to keeping approximately 4 million passenger cars off the road for a year or nearly 7 million tons of waste from being sent to landfills, according to the U.S. Environmental Protection Agency’s Greenhouse Gas Equivalencies Calculator.

Asst. Prof. Juan Pablo Trelles of the Department of Mechanical Engineering is among researchers worldwide trying to address that challenge. Trelles is developing a new process called “plasma-enhanced solar energy” to convert waste carbon dioxide from power plants and industrial factories into sustainable fuels and high-value chemicals.

The National Science Foundation (NSF) recently recognized Trelles’s work with a prestigious faculty early career development prize, called the “CAREER” award. This highly competitive annual program selects the nation’s best young university faculty-scholars “who most effectively integrate research and education within the context of the mission of their organization.”

A close-up view of the photo-thermochemical reactor where carbon dioxide gas is heated by simulated concentrated solar energy to about 1,000 degrees Celsius.

Trelles, who joined the university in 2012, will use the NSF award — worth more than $513,000 spread over five years — to support his research. Working with him in the Re-Engineered Energy Laboratory are Saroj Bhatta and Dassou Nagassou, both Ph.D. candidates in energy engineering; S. Mahnaz Modir Khazeni and Vyasaraj Bhigamudre, both doctoral students in mechanical engineering, and undergraduate student Shyam Sheth. Trelles also collaborates closely with Daniel Sullivan, Ph.D., a lecturer in mechanical engineering.

An Eco-Friendly Alternative to Fossil Fuels

“Carbon dioxide is not very reactive, and no viable technologies for its conversion into fuels and chemicals presently exist,” says Trelles, who is the project’s principal investigator. “In our proposed process, concentrated solar energy heats the gas and an electrical discharge converts it to plasma, or ionized gas, to increase its reactivity.”

Trelles believes that the plasma state of the gas will enhance the rate of carbon dioxide conversion. “The recycling process is potentially sustainable and has a low carbon footprint because it uses waste carbon dioxide and abundant solar energy, and the electricity needed to generate the plasma is provided by solar photovoltaic cells or other renewable energy sources like wind,” he explains.

Microwave radiation generated by a magnetron converts the heated carbon dioxide inside the reactor chamber into plasma, or ionized gas, increasing the efficiency of the carbon dioxide decomposition.

The process can be applied to other gases as well as liquids. “We are particularly interested not only in carbon dioxide but also methane and water. Decomposition of carbon dioxide leads to carbon monoxide, which is a valuable chemical. Carbon dioxide with water can be processed together to synthesize hydrocarbons, which are combinations of hydrogen and carbon atoms. Finally, methane can be decomposed to produce hydrogen gas, a clean-burning fuel,” says Trelles.

He adds: “Our research could lead to economically viable approaches for synthesizing sustainable fuels, providing an alternative to fossil fuels while helping mitigate global greenhouse-gas emissions.”